Adjustable dental chair.



`Patented luly 4, i899. G. HOLTZ.

ADJUSTABLE DENTAL CHAIR.

(Application led July 2, 1896.)

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n. 628,244. Patemdiuly4, |899.

G. HOLTZ.

ADJUSTABLE DENTAL CHAIR. (Appumi'on mea July 2, 189e.)

'(No Model.) v 2 Sheets-Sheet 2.

NITED STATES` GUSTAV HOLTZ, OF JAMESBURG, NEVJERSEY.

ADJUSTABLE DENTAL CHAIR:

SPECIFICATION'fomng part of Letters Patent No. 628,244, dated July 4, 1899.

Application nea July 2,1896. stanno. 597,851. (Nomad.)

y Adjustable Dental Chair, of which the following is a specification.

The present invention relates to improvevments in that class of dental or surgical chairs in which a motive-fluid lifting mechanism is combined with a chair-seat for raising and lowering the latter. In a chair of this character it is necessary to provide means for steadying the chair-seat when it is partiallyT or wholly elevated, and this steadying mechanism must be extensible and contractible in unison with the fluid-controlled lifting mechanism. lt is also desirable that the chair shall be lowered close tothe door, and in some cases the chair-seat must be elevatedy to a considerable height above the oor.

One object of this invention is to provide a chair-lifting mechanism which will embody these desirable features in a manner to give the chair-seat a degree or range of vertical adjustment to an extent heretofore unattainable iu the art and to accomplish these ends by a construction which permits the chair to be lowered quite close to the floor and also attains compactnessin the arrangement of the operating mechanisms when the chair is dropped to its lowest limit.

A further object of the invention is to provide means by which the chair-seat may be rotated in a horizontal plane on its connection with the elevating mechanism, which means prevents the disconnection of the chair-seat from its carrying devices, enables the seat to rotate with minimum friction and wear on the coacting parts, and adapts the seat to be clamped'firmly at any desired place in the revoluble adjustment of said seat.

Wit-h these ends in view the first part of my invention consists in the combination, with a chair-seat, of a three-part telescopic standard having one member attached to the seat for movement vertically therewith and with all of its members slidably connected together for interlocking engagement at 'the limits of the upward travel of the respective members, a fluid-operated three-part telescopic lifting mechanism having a fixed member, a plunger member connected to the seat, and with its intermediate tubular member slidably fitted to the fixed and plunger members to be interlocked therewith at the ,upward limit of the plunger and said intermediate members, and all of the members of the telescopic lifting mechanism being united by Huid-tight joints to provide a two-part extensible piston-chamber that overcomes the leakage of the motive fluid which is forced therein under pressure, and a fluid-pump communicating with the telescopic lifting mechanism.

The invention further consists in the novel combination of mechanisms and in the construction and arrangement of parts, which will be hereinafter more fully described and claimed.

To enable others to understand the inven- ,tion7 Ihave illustrated the same in the accompanying drawings, forming a part of this specification, and in which Figure l is a side elevation of my chair with the seat omitted and showing the telescopic standard raised to its full limit. Fig. 2 is a vertical central sectional elevation with the telescopic standard and the telescopic lifting mechanism lowered and compactly folded, a fragment of the seat-frame being indicated. Fig. 3 is a horizontal sectional plan view illustrating the form of the base, the section being taken on the line a; tc of Fig. 2. Fig. 4 is an enlarged vertical sectional elevation of the telescopic lifting mechanism, showing the same lowered and illustrating 'a vfragment of the chair-base. Fig. 5 is anenlarged plan view of the divided clamp for the chair-seat frame, said clamp forming a ball-race for a ball-bearing between the connect-ion which unites the seat-frame to' the'plunger member of the telescopic lifting mechanism. Fig. 6 is an enlarged vertical A'section through the fluid-pump. Figs. 7 and 8 are views in plan and side elevation, respectively, of the valvebox that controls the admission of themotive fluid from the reservoir-chamber of the chairbase to the pump-cylinder. Fig. 9 is'an enlarged detail view of the manually-operative relief-valve by which the motive fluid in the telescopic lifting mechanism may be permit- IOO ted to escape therefrom into the reservoirf chamber of the chair-base. Fig. lO is an enlarged detail sectional view of a fragment of Y the telescopic standard and illustrating the coupling block or plug by which the chair.

seat frame is connected with one member of the standard and with the telescopic lifting mechanism.

Like numerals of reference denote like and corresponding parts in each of the several figures of the drawings.

In carrying my invention into practice I employ a telescopic standard which consists of three members 2 3 4, that are slidably fitted together for the mem b ers 2 and 3 to fold compactly within the member 4, and the inner tubular member 2 of this telescopic standard is made fast with the chair-seat or with de vices connected therewith, so as to insure the inner standard member 2 heilig lifted with and by the seat when the latter is raised by the action of the telescopic lifting mechanism to be hereinafter described. The lower section or member 4 of this telescopic standard is fast or integral with a substantially fiat base 5, and it will th u`s be seen that the outer lower member 4 is fast with the base, while the inner slidable member 2 of the standard is fast with a coupling which unites the seatframe to the telescopic standard. The inner member 2 of the standard is slidably interlocked with the intermediate member 3 of said standard, and this intermediate member 3 is in turn slidably interlocked with the outer lower member 4 of the standard, such interlockingof the standard members beingeifected at the upward limit of the travel of the members 2 and 3. respectively, so as to prevent the sections of the standards from coming apart when the seat is raised to its full limit. The

. interlocking joints between the extensible members of the standard :3 3 is effected by formiugsimilargrooves 3G in the outer faces of the members 2 3, arranging these grooves to terminate within the ends of the members 2 3 for the formation of stop-shoulders 37, and providing stop-pins 35 on the members 4 and 3 to engage, respectively, with the grooves 36 in the members 3 and 2. Vhen the chairseat is elevated by the action of the lifting mechanism, the inner member 2 of the telescopic standard travels in an upward direction with the chair-seat until the stop-shoulder 37 in the standard member 2 impinges against the stop-pin 35 on the standard member 3, thus effecting the interlocking of the standard members 2 3. A continued elevation of the seat by the action of the lifting mechanism causes the member 2 of the standard to lift the member 3 of said standard, and the elevation of the standard members 2 3 causes the pin 35 of the standard member 4, which is fixed to the base, to travel in the groove 36 of the standard member 3 until the latter has been elevated a sufficient distance to bring its stop-shoulder 37 against the pin 35 of the base, thereby arresting the further Withdrawal or elevation of the connected members 2 3 from the fixed member 4 of the Standard. It is evident that the engaging tongueand-groove connection between the members of the standard prevents rotary movement of the members when elevated or lowered and that the standard members are free to slide or telescope one within the other on the lowering of the seat.

The base 5 has arc-shaped edges on two sides thereof; but on the remaining sides of the base it is recessed or cut away, as shown in Fig. 3, to reduce the area of the base and enable the operator to stand firmly on the fioor and close to one side or the other of the chair.

Within the telescopic standard and disposed centrally in relation to the seat-frame is a three-part telescopic lifting mechanism, one member of which is fast with the base, and the plunger member is connected with the seat-frame to exert an upward lifting action thereon. This telescopic lifting mechanism consists of three members-t1 c. ,a plunger lnember 14, a fixed tubular member 12, and an intermediate slidable tubular member 13. The outer tubular member 12 of the lifting mechanism has a threaded connection at its lower end with the central part of the base, as shown by Fig. 4, whereby this member 12 is made fast and detachable on the base. The plunger member 14 of the lifting mechanism is slidably fitted within the intermediate tubular member 13, and said plunger member is provided with a piston-head and a packing at its lower end. (See Fig. 4.) These members of the lifting mechanism are slidably connected together for interlocking engagement at the upward limit of the members 14 13 in a manner similar to the members 2 3 of the telescopic standard, and this end is attained by the provision of longitudinal grooves 43 in the plunger member 14 and the extensible tubular member 13 and by the employment of fixed stops similar to the stop-pins 35 on the members 13 and l2 to engage with shoulders 44 at the lower terminals of the grooves 43 in the members 14 13. It will be understood that the stop-pins are fast with the members 13 12 to engage with the grooves in the members 14 13, respectively, and these pin-and-groove connections prevent rotary movement of the lifting members one within the other. The practical service of the telescopic lifting mechanism requires an extension-cylinder in which a motive fiuid under pressure is adapted to exert its force against the plunger member 14, and it is important in a device of this character that the motive fiuid be prevented from escaping through the joints at the upper ends of the tubular members 12 13 of Said lifting mechanism. This end is attained in a satisfactory manner in my invention by the employment of the packing-glands 15, vwhich are screwed externally to the upper ends of the tubular members 12 13, and each gland is flanged to embrace the compressible packings 16, which are interposed between the ends of the tubular members and the flanges IOC) IIO

of the glands, so that the packings will engage frictionally with the plunger member 14 and with the tubular member 13, respectively.

The counectionbetween the seat-frame, the inner member 2 of the telescopic standard, and the plunger member 14 of the telescopic lifting mechanism is effected by means of a coupling head or plug 8, which is shown more clearly by Figs. 2 and 10 of the drawings. This coupling head or plug is-provided at a pointrintermediate its end with an annular radial flange 39, and below this flange the plug is provided with a male thread which engages with a female threaded portion at the upper open extremity of the tubular section 2 of the telescopic standard, whereby the plug or head is made fast with the standardv The plug is' member 2 to close the latter. enlarged or widened above the radial flange 2, and the lower face of this enlarged portion of the plug is provided with a bevel or groove 40, as clearly shown by Fig. 4. The circumferential flange 39 of the coupling plug or head extends beyond the standard-section 2 foradistance sufficient to restupon the standard members 3 4 when the standard and seat are lowered, and this circumferential flange 39 of the plug or head provides a broad bearing-surface for an annular clamp 9, that rests upon the flange. This annular clamp is divided radially into two sections, as shown by Fig. 5, and each section is provided with a perforated lug 42, through which is adapted to pass a bolt or screw for the purpose of attaching the clamp member to the seat or seatframe, a portion of which is indicated by Figs. 2 and 10. The annular divided clamp is/fitted around the part of the plug or head 8 which extends above the circumferential iiange 39, and the upper face of this divided clamp has a bevel or chamfer 10, which is opposed to the groove in the plug or head S and forms a ball-race to accommodate the series of bearing-balls 11a. The members of the clamp 9 are connected together by screws 11, and one of these screwsis extended, as shown by Fig. 1, to form a rod by which the operator may adjust the clamp for the purpose of holding the chair-seat against removal from the coupling plug or head 8. It will be observed that the clamp and the head 8 are united together in a manner to prevent disconnection of the seat from the member 2 of the standard, and the ball-bearing permits the seat when the screw is slackened slightly to rotate freely and with minimum friction on the head or plug that is fast with the standard member 2. This plug is provided with a central socket (shown by Fig. 10) to receive the journal at the upper protruding extremity of the plunger member 14, forming a part of the lifter mechanism.

As is usual in the art, the chair-base 5 is constructed of hollow form to provide a reservoir-chamber 17, which surrounds the lower part of the standard member 4, and with this reservoir-chamber communicates the valve lbox or casing of a huid-pump. This duidpump lies externally to the telescopic standard, which is necessary in my chair, because the interior of the standard is occupied practically by the standard members and the telescopic lifting mechanism, and by locating the pump externally to the standard ready access can be obtained to the pump for repairing the same or replacing its active parts when worn. The piston-cylinder 1S of this pump has a threaded engagement with a part of the base 5, above the reservoir-chamber 17 therein, and within, this cylinder is fitted the pumppiston 19, which has a linked connection 2O with an operating-lever 21, the latter being fulcrumed on the standard member 4 and provided with an operating-treadle 22. As'shown by Fig. 2, I prefer to house the pump-cylinder and a part of the operating-lever 21 within a casing, which is slotted to admit of the free movement of the lever 21. The valve box or casing for the pump-cylinder is located within the reservoir-chamber 17 and in the vertical plane of the cylinder 18. This valve box or case 23 has apertured flanges, by which it may be fastened, through thev medium of screws, to a part of the base 5, and within said box or casing 23 is a cage 24, that communicates directly with the foot of the cylinder 18. The valve box or case is provided at its lower end with radial inlet-passages 26, which communicate with the lower part of the cage 24, and a ball-shaped check-valve 25 is loosely fitted within this cage to be seated therein or in the valve-box 23 on a plane above the ports 26 on the descent of the pump-piston 19, thereby preventing the liquid in the pump from flowing back into the reservoir-cham ber when the pump is operated. A valve-cage 29 is fixed within the foot of the member 12, forming a part of the telescopic lifting mechanism, and communication between the valve-cage 29 and the valve-cage 24 withii'the valve box or casing 23 is established by means of a pipe 27. This pipe is contained in the base 5 below the standard, and one end thereof is connected with the valve box or case 23 to open into the cage 24 thereof above the position occupied by the check-valve 25 when the latter is seated to cut off communication from the ports 26 to the pump-cylinder. The valve-cage 29 confines a check-valve 28 in proper relation to the discharge end of the connecting-pipe 27, and this check-valve 28 cuts off communication between the lifting mechanism and the pipe 27 in a manner to prevent the fluid Within the lifting mechanism from flowing through the pipe 27 back to the pump-cylinder, whereby back pressure on the piston 19 is relieved.

The operation of lowering the chair, the lifting mechanism, and the standard is effected by gravity and by releasing the fluid which is con fined under pressure Within said lifting mechanism, and to enable this release of the fluid to be eected conveniently arelief-valve mechanism is provided for manual IOO ICS

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operation by the dentist. A connecting-pipe 31 communicates with the foot of the telescopic lifting mechanism on aplanc above the check-valve 38 when the latter is seated across the delivery end of the pump-pipe 27, and this relief-pipe 3l is attached to a valve-case 30, which is fixed to the base to communicate with the reservoir-chamber 17 thereof. This case of the relief-valve has a downwardlyopening port, as shown by Fig. i), and across this port is adapted to be seated the valve 32, which lies in a plane below the relief-pipe 3l and is adapted to be forced or held upon its seat by the pressure of the ilui'd which is confined within the telescopic lifting mechanism and is adapted to have free access to the casing 30 of the relief-valve. This valve 32 may be readily lifted from its seat by a lever 2323,

having an arm that extends below thc casing 30 and upwardly into the port thereof for the operation of the valve 32, and to this lever is attached a foot-piece 3l. The reliefvalve lever 33 occupies a position substantially at right angles to the treadle 22 of the pump-lever. (See Fig. 3.)

lt is thought that the operation of my invention will readily be understood from the foregoing description taken in connection with the drawings.

Having thus described the invention, what I claim isl. The combination with atelescopic standard, and a plunger-rod of a lifting mechanism, of a coupling plug or head provided with an annular flange and with a groove or channel below the upper edge of said plug, the plug b eing connected to the lifting-plunger and fitting in the upper end of theinner member of the telescopic standard and adapted to have its annular iange rest upon the ends of the standard members when they are lowered, a seat, a sectional clam p attached to the seat and resting upon the ilange in the plug around the grooved part of the latter, and ball-bearings fitted in the race formed by and between the sectional clamp and the grooved plug, substantially as described.

2. The combination with a telescopic standard, and a plunger of a lifting mechanism, of a circumferentially-grooved plug titted lto the lifting-plunger and connected with one member of the telescopic standard and provided with a flange which is adapted to rest upon the standard-sections when they are lowered, a seat, a sectional clamp between the seat and the flange of the plug to rest upon the latter and embracing the grooved plug, and a screw for compressing the clamp upon the plug, substantially as described.

3. In a dental or surgical chair, the combination of a base having one member of a tele` scopic'standard fast therewith and provided with a reservoir, 17, which lies exteriorly to the fast standard member, other telescopic standard members slidably fitted within the fast standard member upon-the base, a lifting ymechanism having an extensible cylinder the outer member of which is attached to the base and the lifting-plunger being operatively connccted to the inner member of the telescopic standard, a pump having its cylinder fast with the base and with a Valve-cage which is arranged within the reservoir, and a pipe connecting said valve-cage with the cylinder of the lifting mechanism, substantially as described.

4. In a dental or surgical chair, the combination with a base, 5, having a fluid-reservoir, and a lifting mechanism situated within the standard, of a pump-cylinder attached rigidly to the base above the fluid-reservoir therein7 an inlet-valve shell situated within the reservoir, attached to the base in alinement with the pump-cylinder, and provided with radial passages that open into the reservoir, a valve within said shell, a check-valve cage in the foot of the'liftiiiig-mechanism cylinder, a pipe, S27, connecting the valve-shell of the pump mechanism with the check-valve of the lifting mechanism, and a relief-valve mechanism connected with the reservoir and with the lifting-mechanism cylinder, as and for the purposes speeilied.

5. ln a dental or surgical chair, the combination with an extensible standard, of a base containing a Huid-reservoir, a seat-lifting mechanism havinga foot-valve, a pump mechanism having its inlet-valve situated within the fluid-reservoir, a pipe, 27, connecting the inlet-valve casing of the pump with the footvalve casing of the lifting mechanism, a relief-valve casing, 230, attached to the base and having a port which discharges to the fluidreservoir, a valve in said relief-valve casing, a relief-pipe connected to the relief-valve casing and to the foot-valve casing above the valves therein, and a treadle-lever having one end arranged to playin the relief-Valve casing to move the Valve therein from its seat, substantially as described.

G. In a dental or surgical chair, the combination with a seat and a base, of a three-part telescopic standard having one member fast with thel base and another member connected with the seat-frame to be lifted thereby, a three-partliftingmechanism having a tubular member fast with the base, and a plunger member connected with the seat-frame, a coupling plug`or head connecting one standard member with the plunger member of the lifting mechanism and with the seat-frame, and a fluid-pump mechanism communicating with said lifting mechanism, substantially as described.

7. In a dental or surgical chair, the combination of a chair-scat, a base, a telescopic standard havinga series of members slidably fitted together, one of said members being connected to said seat to be lifted thereby, a telescopic lifting mechanism housed within said standard to be concealed thereby and having the plunger and tubular members fitted slidably together, said plunger member being connected to' the chair-scat to rise and IOO IIO

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fall therewith, and the outer tubular member fixed to the base, and a Huid-pump mechanism connect-ed to said base and having valved Iiuid connections with the foot of the telescopic lifting mechanism, said pump mechanism being in communication with the lifting lnechanism only through said fluid connections and also supported on the base independently of the rise and fall of the lifting mechanism with the chair-seat, substantially as described.

8. In a dental or surgical chair, the combination of a chair-seat, a vbase having a iiuidreservoir, a telescopic standard having a series of members fitted slidably together, one of which is connected to said seat to be lifted thereby, a telescopic lifting mechanism having the plunger and tubular members itted slidably together, said plunger member being connected to the seat, and the outer tubular member being fixed to the base, a iiuid-pump mechanism connected to said base and having valved iiuid connections with the telescopic lifting mechanism, and means for releasing the iiuid confined in the lifting mechanism and conducting said fluid to the reservoir of the base, substantially as described.

9. In a dental or surgical chair, the combination with a seat, of a telescopic standard having a series of members, one of which is connected with the seat and with the other members slidably connected one to the other for interlocking engagement at the limits of their upward travel, a telescopic lifting mechanism having the plunger and tubular members, said plunger-member being coupled to the seat, and an outer tubular member being fixed in place, and with its several members slidably connected together for interlocking engagement at the upward limits of the travel of the plunger and one tubular member, and a Huid-pump connected with the foot of the lifting mechanism,substantially as described.

10. In adental or surgical chair, the combination with abase, and a seat, of a three-part telescopic standard having a series of members, one of which members is fast with the base, the inner member connected to the seat, and its intermediate member coupled to the aforesaid members to have interlocking engagement therewith at the upwardlimit of the travel of said inner and intermediate members, a telescopic lifting mechanism having plunger and tubular members, with the outer tubular Inember and the plunger member connected to the base and the seat respectively, and with its intermediate tubular member coupled to the outer and plunger members by duid-tight joints, and to have interlocking engagement with the several parts at the upward limits of the travel of the plunger and intermediate members, and a pump mechanismV communicating with the foot of the lifting mechanism, substantially as described.

In testimony that I claim the foregoing as my own I have hereto aflixed my signature in the presence of two witnesses.

GUSTAV HOLTZ.

Witnesses:

ALBERT ULBRIcH, Jon RIGGS. 

